A new study suggests that aromatase inhibitors are more effective than tamoxifen at reducing breast cancer recurrence in postmenopausal women diagnosed with hormone-receptor-positive DCIS (ductal carcinoma in situ). For hormone-receptor-positive DCIS, hormonal therapy such as tamoxifen usually follows surgery. Tamoxifen is given to both premenopausal and postmenopausal women. Aromatase inhibitors are approved only to treat postmenopausal women. The main aromatase inhibitors are Arimidex (chemical name anastrozole), Aromasin (chemical name extremestane) and Femara (chemical name letrozole).
Researchers randomly assigned more than 3,000 postmenopausal women who had been diagnosed with hormone-receptor-positive DCIS to one of two hormonal therapy medicines after surgery and radiation. They later found that 93.5% of women who took Arimidex had no recurrence after 10 years, compared to 89.2% of women who took tamoxifen and had no recurrence after 10 years. Read more about the study here.